Apparatus for forming retaining members

ABSTRACT

Apparatus for forming retaining members on a helical spring having a helical coil section and two tangentially extending ends has a pair of motor-driven bending assemblies arranged facing each other. Each assembly has a pair of fluid motors, one of which bends one of the tangentially extending ends of the spring into a direction which is parallel to the axis of the coil section and the other of which forms the retaining member on the bent spring end. Mounting means is arranged adjacent to and between the two bending assemblies and is arranged to releasably hold at least a portion of the helical coil section of the spring and is positioned to permit the spring ends to be bent and formed by the respective bending assemblies. The fluid motors, which may be either hydraulic or pneumatic, are adjustably mounted in respective clamping stands, and may be locked in a desired position.

Scheckel atent 1 June 27, 1972 [54] APPARATUS FOR FORMING 2,843,159 7/1958 Bonde et a1 ..140/103 RETAINING MEMBERS Prima Examiner-Lowell A. Larson [72] Inventor: Konrad Scheckel, Hagen-Kabel, Germany Atmmg, spencer & Kaye [73] Assignee: Heetmann & Finkensiep KG, Hagen- Kabel, Germany ABSTRACT [22] Fil d; J l 22, 1970 Apparatus for forming retaining members on a helical spring [30] Foreign Application Priority Data July 23, 1969 Germany ..P 19 37 340.1

[52] US. Cl ..140/103 [51] Int. Cl. .....B21f 35/02 [58] Field ofSearch ..140/102, 103; 72/130, 137

[56] References Cited UNITED STATES PATENTS 2,809,675 10/1957 Silko ..140/103 3,405,742 10/1968 Guenther ..140/103 having a helical coil section and two tangentially extending ends has a pair of motor-driven bending assemblies arranged facing each other. Each assembly has a pair of fluid motors, one of which bends one of the tangentially extending ends of the spring into a direction which is parallel to the axis of the coil section and the other of which forms the retaining member on the bent spring end. Mounting means is arranged adjacent to and between the two bending assemblies and is arranged to releasably hold at least a portion of the helical coil section of the spring and is positioned to permit the spring ends to be bent and formed by the respective bending assemblies. The fluid motors, which may be either hydraulic or pneumatic, are adjustably mounted in respective clamping stands, and may be locked in a desired position.

11 Claims, 10 Drawing Figures FIG. 10

I 7 k I i SEQUENTIAL 2V2 FOLLOW-UP CONTROL CONT FIG. lb

INVENTOR Konrad Scheckel ATTORNEYS.

PATENTEDJum I972 SHEET 2 OF 2 FIG FIGB

ATTORNEYS.

APPARATUS FOR FORMING RETAINING MEMBERS BACKGROUND OF THE INVENTION The present invention relates to a device for forming retaining members, such as hooks and eyes, on helical springs having a helical coil section and tangentially extending ends. The ends of the spring are initially bent approximately in a direction parallel to the longitudinal axis of the coil section and the retaining members are formed on them thereafter.

Both motor-driven retaining member forming devices and manual bending tools are known. In both cases of these known devices, however, first one and then the other of the retaining members are bent in succession. Moreover, every desired retaining member shape, such as an eye or hook, requires a corresponding bending tool. Further, a considerable quantity of electronic control equipment is required for the known motor-driven retaining member forming devices.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a simplified device for forming the retaining members of helical springs by initially bending the tangentially extending ends of the helical spring in a direction which is approximately parallel to the axis of the springs coil section and then forming the retaining member on the bent spring end. In particular, it is an object of the present invention to provide such a device which has greater productivity than the known devices.

The above objects are accomplished according to the present invention by providing two motor-driven bending assemblies which are spaced from and adjustable with respect to one another. Each assembly has a device for bending a spring end and a device for forming the retaining member. The two assemblies are arranged facing one another, and a mounting device of small dimensions is arranged between them. The mounting device is fastened to a frame, and releasably encloses at least one portion of the coil section of a helical spring.

A device of the above type is obtained in the manner with which both retaining members of a helical spring can be formed simultaneously.

In a preferredembodiment of the present invention each bending assembly for forming the spring ends, the bends in the spring ends and the retaining members has a pair of rotary fluid motors arranged facing each other. Each fluid motor has: a rotary piston; a housing defining an axis and housing the piston; a drive shaft extending parallel to the axis of the housing and connected to the piston for rotation therewith; and a tool head connected to the drive shaft for rotation therewith. One tool head in each assembly has a pin and a finger extending out from its surface in a direction parallel to the axis of the housing and spaced from one another in the transverse direction of the axis of the housing. This finger and pin act to bend one of the tangentially extending ends of a helical spring. The other tool head in each assembly has a finger, but no pin. The drive shaft of each motor is arranged to extend in a direction axially parallel to the rotary piston housing axis and is spaced therefrom in a direction transverse thereto. Preferably, the rotary pistons are mounted to be rotatably and axially displaceable, and the mountings for the rotary pistons are preferably disposed in pairs at the free end of a rod mounted on a clamping stand. The rods are disposed to be rotatable and lockable in the clamping stands, and the clamp ing stands and/or the rods bearing the fluid motors are axially displaceable and lockable. The two bending assemblies are arranged so that their respective rods are coaxial with one another.

The preferred embodiment described above makes it possible to form retaining members on the helical springs independent of the number of windings in the coil section of the spring. That is, the retaining members at each end of the spring are permitted to have any desired position, or spacing, with respect to one another within the limits of adjustment of the bending assemblies.

Another advantageous feature of a preferred embodiment of the present invention is that devices are provided for selectively varying the angle of rotation of the drive shafts connected to each of the rotary pistons. This is preferably done in such a manner that each rotary piston has associated with it a timer whose switching times can be selectively varied to control the input of the fluid medium being fed under pressure to the fluid motor. The preselected switching times of the timers is preferably indicated by appropriate indicating devices.

A wire forming device according to the preferred embodiment of the present invention permits the formation of, for example, more or less closed eyes without special bending tools being required for the purpose.

It has, moreover, been found to be particularly advantageous, in order to shorten the idle periods of the device, to dispose a switch for the control of the fluid motors at the mount for the helical spring holding device. Preferably, this switch is arranged so as to be influenced by the mounting when the holding device is in its closed position.

The fluid motors of the preferred embodiment of the present invention may be, for example, either hydraulic or pneumatic motors.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. la and lb, which are partly in cross section, are partly schematic front elevational views of a device for forming retaining members on helical springs according to the present invention. FIG. 1a is a left portion of the device, including the spring mounting device, and FIG. 1b is the right-hand portion of the device.

FIGS. 2 through 5 are schematic views showing a sequence of four different operating positions of the bending tools of one of the bending assemblies shown in FIGS. la and lb.

FIGS. 6 through 9 are elevational views of a selection of helical springs having retaining members which can be produced with the device of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. la and lb show a pair of substantially identical motordriven bending assemblies 24, 24'. Each assembly 24,24 has a suitable known clamping stand 2 and a cylindrical rod 3 which is rotatably and axially displaceable as well as lockably arranged in the respective headstock 2. This movement and lockability may be achieved by providing each clamping stand 2 with a split-clamp type arrangement and a plurality of bolts 23, as can be best seen in FIG. lb. As is well known, the bolts 23, may be loosened to pennit movement and tightened to prevent movement of the rod 3. The clamping stands 2 are mounted on a machine frame member 1 in such a manner that the rods 3 of each assembly 24,24 are coaxial to one another.

At each one of the end portions of rods 3 facing one another, a clamping member 4,4 is provided, each of which is designed to hold a pair of fluid motors 5, 6 and 7, 8 respectively. The fluid motors 5-8 are rotatably and axially displaceable and lockably disposed in their respective clamping members 4,4. The clamping members 4,4 may be mounted for movability and lockability in a similar manner as rods 3 are mounted in clamping stands 2. That is, by means of a splitclamp arrangement 34 and a plurality of bolts 23' (See FIG. lb). This mounting arrangement of the clamping members 4,4 permits them to be adjusted independently of one another in the direction of the longitudinal axis of the respective rods 3. The motors 6 and 8 are held in place by a pair of respective plates 28,28 mounted on a plate 30 of clamping members 4. A plurality of pins 25 are mounted on plate 30 to engage in respective slots 26 in plates 28,28. As can be best seen in FIG. 1a, portions of plates 28,28 are shaped to fit around the housing of motors 6 and 8. Pins 25 in slots 26 permit adjustment of plates 28,28 with respect to plate 30 to provide the adjustable mounting for motors 6 and 8 referred to above. Clamping members 4 have a plate 31 and adjustable segments 29 (only one of which can be seen in the drawings), and function to hold motors 5 and 7 in a manner similar to clamping members 4 described above.

An adjustment device including a crank 11 defining a slot 38 and a bracket 11' is provided for adjustably mounting clamping members 4'. Pivot members 27,27 and clamping members 25' connect the various elements together. This adjustment device permits pistons 6 and 7 to be selectively brought from their normal positions at right angles to rods 3 to, for example, a position as shown in FIG. 1a.

All other clamping pliers 4,4 can be shaped the same way as the member 4 in FIG. 1a, so that they too are adjustable and lockable.

As can be seen in the cut away portion of FIG. 1b, the suitable known rotary fluid servo-motors 6 and 8 have a shaft 37 which is connected by means of suitable known gears 40 to a drive shaft 9. Shaft 9 is arranged parallel to the axis of the housing of the respective servo-motor. A tool head 10 is fastened to the free end of shaft 9, and has on its outer face a finger 18 and a pin 20, each extending out from the surface of tool head 10 parallel to the axis of the motor housing and spaced from one another in the transverse direction of the axis of the motor housing. Motors 5 and 7 are identical to motors 6 and 8, except that they do not have a pin 20.

A mounting member 12 (FIG. 1a) is rigidly attached to frame 1 in a known manner and is arranged between the clamping stands 2 on a line generally through the axis of the rods 3. Mounting member 12 has a pair of clamping jaws 14,14 which can be manually compressed by means of a lever 13 to grip at least a portion of the coil section of a helical spring. One of jaws 14,14 is provided with an abutment 19 (see FIGS. 2 and 3). In the embodiment shown in the drawings, jaw 14' may be attached to lever 13 and lever 13 may be mounted for vertical movement in guide members 39 so that jaws 14,14 may be brought together. Jaws 14,14 may be constructed of any suitable known material; preferably a hard material.

A suitable, known fluid pulse generator 16 is also mounted in a known manner to one of the frame members 39 of mounting members 12. This generator 16 acts to control the rotary pistons, and is actuated by a pin 33 mounted on lever 13 which engages a lever 32 when the jaws 14,14 are in their closed, gripping position.

A suitable, known timer is also provided to control each motor 5 through 8. For the sake of simplicity, only FIG. 1a shows timers connected to a respective motor; that is, timer 35 connected to motor 5 and timer 36 connected to motor 6. These timers vary the angle of rotation of the drive shafts 9 by having switching times which are selectively variable in a known manner for controlling the input of a fluid working medium under pressure being supplied to the respective motors. Indicator devices 22 (FIG. 1a), which are of a known type, may be used to indicate the preselected switching times of each of the timers. These devices 22 may also be provided in a known manner with a scale on which the preselected angle of rotation can be read.

For the sequence control of the bending tool heads timers are provided of the conventional type which may also be set in such a way that the impulse giver 16, actuated by hand lever 13, gives an impulse to a first timer which switches on this timer. The latter than switches on rotary pistons 6 and 7. After the preset time the timer switches the rotary pistons 6 and 7 ofi" and a further timer on which first switches rotary pistons 5 and 8 on and after the preset time off again, the timers then returning to their starting position.

These well-known and conventional timers also permit the first timer only one-fifth second after switching off rotary pistons 6 and 7 to switch on the timer actuating rotary pistons 5 and 8 to ensure a l/5-second break between the individual bending procedures.

OPERATION The operation of the retaining member forming device described above will now be set out with the aid of FIGS. 2 through 5.

When at least a portion of the coil section of a helical spring 15 is gripped by jaws 14,14 of mounting member 12 by a downward movement of lever 13, pin 33 engages lever 32 and actuates the pulse generator 16. This provides the fluid servo motors with fluid from a suitable, known fluid source (not shown). The motors 5-8 may be either hydraulic or pneumatic motors. Initially, the tool heads 10 of each of the motors 5 through 8 are in the respective positions shown in FIG. 2; which uses, for example motors 7 and 8. Once fluid has been sent to the respective motors by the pulse generator 16, however, the tool heads 10 are rotated and take up the position shown in FIG. 3. In the process, the tangentially extending spring end 17 (FIG. 2) is bent by means of finger 18 on tool head 10 of motor 7 to a position substantially parallel to the axis of the coil section of the spring 15 (FIG. 3) by bending it around the abutment 19. The angles of rotation of the respective fluid motors are controlled by the timers referred to above. Upon completion of this operation, the spring end 17 although only one is shown in FIGS. 2 through 5, it is understood that similar operations are taking place simultaneously at each end of the spring 15, with motors 5 and 6 being equivalent to motors 7 and 8, respectively extending between a pin 20 and a finger 18 on the tool head 10 of the associated fluid motor; in this case, it would be motor 8 (See FIGS. 4 and 5). Sequential control device 41 now actuates motor 8 to cause too] head 10 to rotate and bend the spring end 17 about the pin 20 due to the pressure exerted on spring end 17 by the finger 18. That is, the spring end 17 is bent from the position shown, for example, in FIG. 4, to the position shown, for example, in FIG. 5 to form, for example, a hook. Once again, the angle of rotation of the piston of the motor 8 is controlled by its respective timer. As stated above, the preselected switching times of the respective timers can be seen on the indicator devices 22. After the retaining member; for example, hook 21; has been formed, the follow-up control 42 causes the fluid motors to return automatically to their starting positions.

The speed of the drive shafts 9 and, thus, the tool heads 10 is, due to the transmission of torque from the piston shafts 37 of the fluid servo-motors) by means of gears 40. The speed of the drive shafts 9 is a function of the speed of the piston shafts 37 and is simultaneously reduced with them.

It is also possible within the scope of the present invention to provide means to automatically bring the springs 15 from a magazine or storage container (not shown) to the mounting member 12 and to releasably clamp them in and to remove them therefrom after the retaining members have been fonned thereon.

FIGS. 6 through 9 show several examples of possible configurations of retaining members formed by the bending assemblies of the present invention.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

I claim:

1. Apparatus for forming a retaining member on a helical spring having a helical, longitudinal axis defining, coil section and two tangentially extending ends, comprising in combination:

a. a motor-driven bending assembly which includes:

i. means for bending one of the tangentially extending ends of the spring into a direction which is parallel to the axis of the coil section; and

ii. means, separate from said bending means, for forming hooks on the bent spring end;

b. mounting means arranged adjacent to said bending assembly for releasably holding at least one portion of the helical coil section of the spring and positioned to permit said one spring end to be bent and formed by said bending assembly; and

a frame member, said mounting means having small dimensions and being permanently mounted on said frame member,

said bending and forming means each having a fluid motor with a rotary piston, a housing defining an axis and housing said piston, a drive shaft extending parallel to the axis of said housing and connected to said piston for rotation therewith, and a tool head connected to said drive shaft for rotation therewith, said tool head having a finger extending outwardly therefrom the parallel to the axis of said housing, said tool head of said forming means also having a pin extending parallel to said finger and spaced from said finger in the transverse direction of the axis of said housing, said pin and said fingers of said tool heads being arranged facing each other to engage one of said tangentially extending ends of the helical spring, and said mounting means having an abutment arranged to cooperate with said finger on the tool head of said bending means.

2. Apparatus as defined in claim 1, further including means for mounting said fluid motors for rotation about and displacement along the axis of said housing.

3. Apparatus as defined in claim 2, further including a clamping stand and a rod defining a longitudinal axis connected to said mounting means for said fluid motors and mounted in said clamping stand to be rotatable and lockable therein, and at least one of said clamping stand and said rod being arranged to be displaceable and lockable in a direction parallel to the axis of said rod.

4. Apparatus as defined in claim 3, wherein said mounting means for said fluid motors has a clamping member for each fluid motor which are lockable and can be compressed by means of screws and at least one of which is mounted on said rod to be pivotal about an axis which extends transverse to the longitudinal axis of said rod.

5. Apparatus as defined in claim 4, further including means for selectively varying the angle of rotation of said drive shafts.

6. Apparatus as defined in claim 5, wherein said varying means has timing means having switching times which are selectively variable associated with each fluid motor for controlling the input of a fluid medium under pressure.

7. Apparatus as defined in claim 6, wherein said varying means has indicating means associated with said timing means for indicating preselected switching times of said timing means.

8. Apparatus as defined in claim 7, wherein said mounting means for releasably holding at least one portion of the helical coil section has a switch means for controlling said fluid motors, said switch means being influenced by said mounting means when it is in its closed position.

9. Apparatus as defined in claim 8, wherein said fluid motors are hydraulic motors.

10. Apparatus as defined in claim 8, wherein said fluid motors are pneumatic motors.

11. Apparatus as defined in claim 8, wherein there are two motor-driven bending assemblies arranged adjacent and on opposite sides of said mounting means for releasably holding at least one portion of the helical coil section for simultaneously forming retaining members from each of the two tangentially extending ends of the helical spring, and said rods of said two assemblies being arranged coaxially to one another. 

1. Apparatus for forming a retaining member on a helical spring having a helical, longitudinal axis defining, coil section and two tangentially extending ends, comprising in combination: a. a motor-driven bending assembly which includes: i. means for bending one of the tangentially extending ends of the spring into a direction which is parallel to the axis of the coil section; and ii. means, separate from said bending means, for forming hooks on the bent spring end; b. mounting means arranged adjacent to said bending assembly for releasably holding at least one portion of the helical coil section of the spring and positioned to permit said one spring end to be bent and formed by said bending assembly; and c. a frame member, said mounting means having small dimensions and being permanently mounted on said frame member, said bending and forming means each having a fluid motor with a rotary piston, a housing defining an axis and housing said piston, a drive shaft extending parallel to the axis of said housing and connected to said piston for rotation therewith, and a tool head connected to said drive shaft for rotation therewith, said tool head having a finger extending outwardly therefrom the parallel to the axis of said housing, said tool head of said forming means also having a pin extending parallel to said finger and spaced from said finger in the transverse direction of the axis of said housing, said pin and said fingers of said tool heads being arranged facing each other to engage one of said tangentially extending ends of the helical spring, and said mounting means having an abutment arranged to cooperate with said finger on the tool head of said bending means.
 2. Apparatus as defined in claim 1, further including means for mounting said fluid motors for rotation about and displacement along the axis of said housing.
 3. Apparatus as defined in claim 2, further including a clamping stand and a rod defining a longitudinal axis connected to said mounting means for said fluid motors and mounted in said clamping stand to be rotatable and lockable therein, and at least one of said clamping stand and said rod being arranged to be displaceable and lockable in a direction parallel to the axis of said rod.
 4. Apparatus as defined in claim 3, wherein said mounting means for said fluid motors has a clamping member for each fluid motor which are lockable and can be compressed by means of screws and at least one of which is mounted on said rod to be pivotal about an axis which extends transverse to the longitudinal axis of said rod.
 5. Apparatus as defined in claim 4, further including means for selectively varying the angle of rotation of said drive shafts.
 6. Apparatus as defined in claim 5, wherein said varying means has timing means having switching times which are selectively variable associated with each fluid motor for controlling the input of a fluid medium under pressure.
 7. Apparatus as defined in claim 6, wherein said varying means Has indicating means associated with said timing means for indicating preselected switching times of said timing means.
 8. Apparatus as defined in claim 7, wherein said mounting means for releasably holding at least one portion of the helical coil section has a switch means for controlling said fluid motors, said switch means being influenced by said mounting means when it is in its closed position.
 9. Apparatus as defined in claim 8, wherein said fluid motors are hydraulic motors.
 10. Apparatus as defined in claim 8, wherein said fluid motors are pneumatic motors.
 11. Apparatus as defined in claim 8, wherein there are two motor-driven bending assemblies arranged adjacent and on opposite sides of said mounting means for releasably holding at least one portion of the helical coil section for simultaneously forming retaining members from each of the two tangentially extending ends of the helical spring, and said rods of said two assemblies being arranged coaxially to one another. 